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UserspaceEmulator: Raise an error on FPU stack underflow

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Accessing an unset part of the FPU stack should not be a simple warning,
but should trigger the FPU exception mechanism.
This commit is contained in:
Hendiadyoin1 2021-07-23 14:22:19 +02:00 • committed by Linus Groh
parent 0d6d780183
commit 83f50a1507
3 changed files with 6 additions and 15 deletions
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2
Userland/DevTools/UserspaceEmulator/SoftCPU.h
View file

@ -267,7 +267,7 @@ public:
ValueWithShadow<u8> dl() const { return const_gpr8(X86::RegisterDL); } ValueWithShadow<u8> dl() const { return const_gpr8(X86::RegisterDL); }
ValueWithShadow<u8> dh() const { return const_gpr8(X86::RegisterDH); } ValueWithShadow<u8> dh() const { return const_gpr8(X86::RegisterDH); }
long double fpu_get(u8 index) const { return m_fpu.fpu_get(index); } long double fpu_get(u8 index) { return m_fpu.fpu_get(index); }
long double fpu_pop() { return m_fpu.fpu_pop(); } long double fpu_pop() { return m_fpu.fpu_pop(); }
MMX mmx_get(u8 index) const { return m_fpu.mmx_get(index); }; MMX mmx_get(u8 index) const { return m_fpu.mmx_get(index); };

14
Userland/DevTools/UserspaceEmulator/SoftFPU.cpp
View file

@ -38,15 +38,6 @@ ALWAYS_INLINE void warn_if_uninitialized(T value_with_shadow, const char* messag
namespace UserspaceEmulator { namespace UserspaceEmulator {
ALWAYS_INLINE void SoftFPU::warn_if_fpu_not_set_absolute(u8 index) const
{
if (!fpu_is_set(index)) [[unlikely]] {
// FIXME: Are we supposed to set a flag here?
// We might need to raise a stack underflow here
reportln("\033[31;1mWarning! Read of uninitialized value on the FPU Stack ({} abs)\033[0m\n", index);
m_emulator.dump_backtrace();
}
}
ALWAYS_INLINE void SoftFPU::warn_if_mmx_absolute(u8 index) const ALWAYS_INLINE void SoftFPU::warn_if_mmx_absolute(u8 index) const
{ {
if (m_reg_is_mmx[index]) [[unlikely]] { if (m_reg_is_mmx[index]) [[unlikely]] {
@ -62,10 +53,11 @@ ALWAYS_INLINE void SoftFPU::warn_if_fpu_absolute(u8 index) const
} }
} }
ALWAYS_INLINE long double SoftFPU::fpu_get(u8 index) const ALWAYS_INLINE long double SoftFPU::fpu_get(u8 index)
{ {
VERIFY(index < 8); VERIFY(index < 8);
warn_if_fpu_not_set_absolute(index); if (!fpu_is_set(index))
fpu_set_stack_underflow();
warn_if_mmx_absolute(index); warn_if_mmx_absolute(index);
u8 effective_index = (m_fpu_stack_top + index) % 8; u8 effective_index = (m_fpu_stack_top + index) % 8;

5
Userland/DevTools/UserspaceEmulator/SoftFPU.h
View file

@ -48,7 +48,7 @@ public:
ALWAYS_INLINE void set_c2(bool val) { m_fpu_c2 = val; } ALWAYS_INLINE void set_c2(bool val) { m_fpu_c2 = val; }
ALWAYS_INLINE void set_c3(bool val) { m_fpu_c3 = val; } ALWAYS_INLINE void set_c3(bool val) { m_fpu_c3 = val; }
long double fpu_get(u8 index) const; long double fpu_get(u8 index);
void fpu_push(long double value); void fpu_push(long double value);
long double fpu_pop(); long double fpu_pop();
@ -246,7 +246,7 @@ private:
set_tag_from_value_absolute((m_fpu_stack_top + index) % 8, val); set_tag_from_value_absolute((m_fpu_stack_top + index) % 8, val);
} }
ALWAYS_INLINE bool fpu_isnan(u8 index) const ALWAYS_INLINE bool fpu_isnan(u8 index)
{ {
return isnan(fpu_get(index)); return isnan(fpu_get(index));
} }
@ -279,7 +279,6 @@ private:
} }
void warn_if_mmx_absolute(u8 index) const; void warn_if_mmx_absolute(u8 index) const;
void warn_if_fpu_absolute(u8 index) const; void warn_if_fpu_absolute(u8 index) const;
void warn_if_fpu_not_set_absolute(u8 index) const;
void mmx_common() { m_fpu_tw = 0; } void mmx_common() { m_fpu_tw = 0; }